when "the base model for your avatar does not exist"

[Fallen Angelok]

hi. hey. hello.
So for couple of months ( or a year now ) I have been having problems with my avatar.
When I try to save it, it says "The base model for your avatar does not exist. please reconfigure your avatar"
what do I do?
I have been having this problem for ages! cry crying
Thank you gaia_angelleft gaia_crown gaia_angelright